


you came in like a wave

by chininiris



Category: Fire Emblem: Fuukasetsugetsu | Fire Emblem: Three Houses
Genre: Angst, F/M, Fire Emblem: Three Houses Church Route Spoilers, Fluff, Fluff and Angst, Original Character(s), Other Additional Tags to Be Added, Post-Canon, Spoilers for Seteth and Flayn's Supports, recurring themes are:, that's just their little girl ok
Language: English
Status: In-Progress
Published: 2020-02-25
Updated: 2020-03-27
Packaged: 2021-02-28 02:15:39
Rating: Teen And Up Audiences
Warnings: No Archive Warnings Apply
Chapters: 2
Words: 3,827
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/22896286
Author URL: https://archiveofourown.org/users/chininiris/pseuds/chininiris
Summary: i. oceanByleth hums, gazing at the wide expanse of ocean and its different shades of blues and greens and inbetweens. “This is nice.”“Yes.” Seteth turns his eyes to the water and smiles as Flayn’s head breaks through the surface. “We haven’t been here in a while.”Various setleth scenarios in the form of drabbles, ficlets, and such.
Relationships: My Unit | Byleth & Seteth, My Unit | Byleth/Seteth
Comments: 22
Kudos: 69





	1. ocean

**Author's Note:**

> *chinhands* hello there 
> 
> I've been in a certain setleth mood for a few weeks now, and it wasn't until last week when I caved in and started binge reading a ton of fanfics. It all started thanks to a certain scene I wrote for my dimileth fic, which I had to change (read: force Seteth to talk about his late wife) to make it more platonic. And now I changed it again to make it 100% setleth romance :^)
> 
> Title is from [Sunshine Riptide](https://www.youtube.com/watch?v=go3_Dexzsno). Enjoy!

“What do you want to do for your birthday?” Byleth asks one afternoon a few weeks before Flayn’s birthday is to take place, and Flayn earnestly replies that she would like to see the ocean again.

“But I don’t think my father will agree to it,” she confesses forlorny in the privacy of Byleth’s chambers where they are drinking tea and sharing a tray of sweet baked treats, then adds in her usual upbeat tone, “Oh, but can we have Teutates Herring for dinner? I adore how the new cook prepares it!” 

Byleth sips her tea and complies with a smile, but within the walls of her office, she presses Seteth until he yields the way only she knows how.

And that’s how they end up in Rhodos Coast for a couple of days, just the three of them and the wyverns Seteth insisted they should take. Byleth steps onto the sun-warmed sand, the granules shifting under her weight as she walks towards the waves gently crashing over the shore. She’s wearing her black top and shorts again for the first time in so long, discarding the royal regalia and the usual circlet. She’s lost some muscle mass from moons of inactivity, and by default some definition, but Sothis’s crest stone ensures that her strength remains intact. 

Byleth has seen her fair share of beaches around Fódlan from all the years of travel with her father, but the last time she recalls ever being to the coast was when Seteth came to this very place all those years ago to defend it from the Western Church.

Flayn is already playing in the clear waters of the sea, wearing a navy blue one-piece swimsuit with frills around the hips. She disappears beneath the waves for minutes at a time, but always resurfaces before Byleth can get worried for her safety.

Byleth finds herself smiling. Her relationship with Flayn and Seteth is easy, far easier than hers with Rhea had been and continues to be. She owes the archbishop her life, quite literally, but to know that Rhea only took a liking to her because she had hoped Sothis would take over her body leaves a sour taste in her mouth that lasts to this day.

With Seteth and Flayn, Cichol and Cethleann, things are easier, simpler. He was distrustful of her at first, but learned to accept her as a close ally with whom he could trust his daughter’s life and his own, and learned to care for her. And Flayn had always been so friendly, so earnest in her attempts to befriend others, so caring for those she barely knew. Byleth suspects she was her first friend, and if that truly is the case, then she is honored for it.

Seteth had once said they were like family. The familiar weight of the ring on her finger solidifies that. 

He comes to stand by her side, the waves lapping up at their bare feet. He’s dressed in a loose white shirt with the laces at the collar undone, pants rolled up to his knees, and a straw hat placed on his head to shield his eyes from the bright sun. He holds the fishing rod as he would wield a lance, and carries a small bucket of fish bait in his other hand. 

Her lips quiver as she tries to suppress a giggle, but she’s unsuccessful. “What’s so funny?” The mild glare he gives only makes it funnier. Still, his eyes glimmer with affection.

“I have never seen you this casual and dressed down, is all,” she explains, lacing her fingers behind her back and rocking on the heels of her feet.

“We are in a beach. I have to dress the part,” he replies matter-of-factly and squares his shoulders. She frowns momentarily; this trip is as much for Flayn to enjoy some time at the beach as it is for them to relax. Being a ruler is exhausting, and being a Prime Minister is just as taxing. “Besides, this should come as no surprise. Should I remind you that you see me dressed down every night?” 

“As if I could ever forget that.” As dusk falls and her body grows wearier, Byleth starts looking forward to sleeping in his arms at night. “But pajamas and actual casual clothes aren’t the same.”

“I suppose not.” He concedes, looking her simple outfit over. Byleth will take up any and every opportunity not to wear the usual white dress, but Seteth will always wear his formal robes, even if they are going for a horseback ride or making a quick trip to the nearest town. 

Byleth hums, gazing at the wide expanse of ocean and its different shades of blues and greens and inbetweens. “This is nice.”

“Yes.” Seteth turns his eyes to the water and smiles as Flayn’s head breaks through the surface. “We haven’t been here in a while.” 

She wonders how long that felt to him, to them, being immortal and all. Perhaps the war might have slowed down their perception of the passage of time. She can’t say time has started to drag on for her yet, having spent a good chunk of her recent years deep asleep. Maybe a decade or two into the future and she will start feeling its effects on her life. 

Byleth looks at the shrine on a tiny islet not too far from the shore, the black stones carved with writings she didn’t get to read the last time. “We should do this more often.”

“There is far too much work do be done still to be thinking of taking vacations.” He reminds her, ever the advisor and voice of reason, and Byleth resists the urge to sigh. 

“Could you indulge me in my fantasies just once?” Byleth just wants to relax and make hypothetical plans of building a beach house or traveling down to the coast more often. She doesn’t need a reminder of the pile of paperwork she left behind on her office desk.

“I thought I already-”

“You know what I mean.”

Seteth chuckles, and she crosses her arms and looks away. “Patience, my love. Soon we will have all the time in the world to ourselves.” 

Despite her slight exasperation at his antics, Byleth can’t fight back the smile that blooms on her lips as she turns to look at him again. “I like the sound of that.” 

“So do I.” Smiling, Seteth points at a nearby pier with his fishing rod. “Care to join me?” 

Byleth takes the bucket of bait from his hand in order to intertwine their fingers. Seteth isn’t fond of public displays of affection, so to be able to do this in broad daylight and out in the open is a rare opportunity she’s not going to let pass. He keeps his touches to a minimum even when Flayn is the only one around, merely touching Byleth on the wrist or hand and never for too long. 

They make their way over to the pier leisurely, with Byleth kicking up water like the carefree kid she never was, and Seteth shaking his head at her with a soft smile on his lips. The wood of the pier is hot under her wet feet, and they quickly make their way over to the edge where they sit with legs dangling above the water, the bucket of bait placed to her left, their thighs brushing together. 

Byleth hooks a bait in place and watches as he casts the line, the bobber swaying gently with the waves. Being here makes her want to fish too, but she admits she’s too lazy to head back to camp to retrieve her own fishing rod. 

She leans back on her hands, tossing her head back to feel the warm sunshine on her face. With her hair tied up in a ponytail, the act reveals the pale skin of her neck, and she can feel Seteth’s verdant gaze tracing the line of her throat. Byleth turns her head in his direction and lifts a brow, leaning forward with a smile. With Flayn still splashing in the water, Seteth indulges her and leans in to place a chaste kiss on her lips. 

Her father’s - her mother's - silver ring glints under the sun, hanging from a chain around his neck. It’s too small to fit any of his fingers, but she doesn’t mind that it’s not on display all the time. Seteth rarely takes the chain off, and every morning the ring is resting against his sternum as he dresses for the day. 

Besides, people know better than to try to flirt with the Queen’s Prime Minister and husband. 

Still looking at each other, she almost misses the bobber sinking underwater. Byleth jerks away from him and towards the bobber, as if she can pull it out with her will alone. “The fish-!”

He reacts too late, pulling the hook from the water with no bait or fish in sight. “I’m afraid I haven’t gotten any better at fishing over the years.” 

Well, maybe if they weren’t too distracted making moon eyes at each other, he would have reeled that one in. She holds out her hand. “Let me catch a few fishes for dinner and lunch, and then you can have your fun.” 

Seteth gives her a dry look, but hands over the fishing rod without complaint.


	2. ii. legendary

**Summary for the Chapter:**

> “Is it true she married Saint Cichol?” One of them asks.
> 
> Flayn shares a sidelong glance with him. Quietly, he nods and decides to tackle this topic himself. “Yes, it is. After the war was won, Saint Seiros stepped back from her position as Archbishop, and with no royalties or lords left to take the mantle of ruler, the Goddess Reborn accepted to lead the newly united Kingdom of Fódlan back to stability.”

He watches from the entrance of the Chapel of Saints as Flayn explains the history of the Four Saints to a group of middle schoolers. So many years after their departure, Garreg Mach was turned into a museum, and they have found themselves here once again, working to administer what once was their home, aiming to share its history with outsiders in guided tours.

She’s doing a splendid job, relaying to the students the modified story of the long six year war that wracked Fódlan, of how Saints Cichol and Cethleann had returned to aid Saint Seiros once again, and how the Goddess Reborn fought on their side to lead them through the dark times when Seiros went missing. 

Flayn has grown so much, her face now matured into one of a young adult’s. Gone are the round cheeks, the childlike and innocent features, the dresses with ruffles and bows, the tight curls of her hair. She is dressed in an uniform that is reminiscent of the one the students wore so long ago, now redesigned to fit this day and age, made to tell apart museum staff from visitors. The golden hairpins tangled in sea green locks are the same from that era, though. 

Seteth had come to the cathedral with the intent of talking to the choir after their daily practice, but the sight of his daughter guiding a group of students made him delay his plans. He looks on and catches the hint of sadness in her voice as she talks about the nobles who fought in the war, her classmates, now long gone and lost to the hands of time. 

It hadn’t been easy to the both of them when former students and classmates fell ill and passed away one by one, but his dear wife had suffered the most. She had been with them from the start, guiding them through practice drills and real battles, winding back time to keep them alive, but for all of her godly powers and the divine soul merged with her own, she could not save them from certain death. 

Decades, centuries later and the pain has lessened some, though Flayn still smiles sadly at the memory of her deceased husband whenever he is brought up during those tours. Seteth had wanted to shield her from all harm and pain, especially from experiencing the loss of loved ones again, but she had been adamant in experiencing both love and loss like her peers. 

Flayn approaches him once she’s done with her lecture, letting the students take a closer look at the statues of the Four Saints. She’s grown- matured, for she’s still smaller than him - smaller than Byleth even.

“Hello, father.” She smiles up at him and laces her hands behind her back. He will never get tired of seeing her lips pulling into a large smile now that she has the freedom to call him as such. “What do you think? Was it good?” 

“It was perfect,” he praises, reaching out to squeeze her arm affectionately. “You are the best guide this museum has ever seen.” 

Flayn giggles, bringing up a hand to her face, pressing delicate fingers to her lips. One of the students turns back to her and approaches, a young boy who faintly reminds him of Ashe. “Is there a statue of the Goddess Reborn here?” 

“There is one in the courtyard near the dining hall,” Flayn supplies, smiling gently. It is placed in one of the gazebos, the one that leads to the Holy Tomb. It seemed fitting to put it there, and it’s less conspicuous than a floating, glowing orb that attracted so many curious stares. The statue depicts Byleth in her enlightened garbs, hand lifted up to cast magic as the other wields a sword. The features of the sculpture don’t do her justice. “We will be going there after we visit the classrooms.” 

The students follow her out of the chapel, and Seteth finds himself walking alongside his daughter as she takes them to one of the side exits of the cathedral, towards the Goddess Tower. “Is it true she married Saint Cichol?” One of them asks.

Flayn shares a sidelong glance with him. Quietly, he nods and decides to tackle this topic himself. “Yes, it is. After the war was won, Saint Seiros stepped back from her position as Archbishop, and with no royalties or lords left to take the mantle of ruler, the Goddess Reborn accepted to lead the newly united Kingdom of Fódlan back to stability.” 

The kids listen intently as he speaks. He can feel their curious gazes prodding the back of his head, eager to hear more of the savior. “One evening, days past her coronation, it is said she visited the Goddess Tower, seeking respite from her duties.” 

Outside, the Goddess Tower reaches up to the clear blue sky, still closed to the public to this day. Vines creep up the ancient walls and a few cracks can be spotted in the stone, but the construction remains standing strong. 

“It was then that Saint Cichol approached her and confessed his love.” He smiles to himself, aware of his daughter’s gaze on his face. The students approach the parapet to get a closer look at the tower. “They got engaged that very night and announced their engagement months later to the public.” 

“Why did they wait so long?” Another one inquires, eyes as blue as Caspar’s had once been. 

“Saint Cichol wanted to restore and stabilize Fódlan before announcing their relationship,” Flayn explains, and a student boos from within the small crowd. Frowning as a faint blush colors his cheeks, Seteth looks at the students and catches one of them rolling her pink eyes. That certainly brings back memories. “Historians believe they married in this cathedral.” 

They turn back around to leave the premises of the cathedral, heading for the classrooms next. “What happened to them?” 

“They appointed a trustworthy ally as the new ruler,” Flayn begins, hands neatly folded in front of her, “and left Fódlan altogether to enjoy the rest of their days in peace.” 

“So they retired?”

“You could say so, yes.”

“Are they still out there?”

“No one knows.” 

As they come close to the bridge, a familiar figure approaches their group, and his heart instinctively skips a beat. Under the morning sun, Byleth’s pale hair seems to shine as it flutters in the gentle breeze. She carries the newest addition to their family on her hip, their little girl hugging a fish plush that was handmade by Flayn to her chest.

For the longest time, it was just the three of them travelling around Fódlan to sightsee, eventually going past its borders to Almyra, Brigid, even Dagda. They talked about having children, but there was no rush to conceive. With Fódlan at peace and no threat in sight, they had all the time in the world ahead of them.

And besides, they rather enjoyed the whole process of trying to conceive a child, the nights spent rolling in soft bed sheets, touching and exploring one another and never getting tired of it.

It was centuries after their marriage, shortly after they wormed their way into Garreg Mach once again, that Byleth started feeling the telltale symptoms of a pregnancy. He had been beyond himself with joy, and Flayn was eagerly looking forward to meeting her new sibling. 

Their little princess is now three years old and just as beautiful as her mother, with hair of a slight darker shade and eyes the same color as his. She is perfect in every way, and his heart threatens to burst whenever he looks at her, at the three of them. His family.

Niamh blinks at him and reaches out a little hand in his direction. “Papa!” 

He can’t stop himself from approaching, taking her hand and bending down to press a kiss to the top of her head. Byleth is smiling softly when he pulls back, though her eyes shine with a bit of amusement. He’s not very fond of public displays of affection of any kind, but he will allow himself this indulgence just this once. 

“Hello, Niamh!” Flayn approaches them, momentarily stepping away from the group of students to greet her little sister. Niamh turns her attention to Flayn and forgets all about Seteth, stretching both arms in her direction. He quickly snatches the plush before it can hit the ground.

Byleth huffs a quiet laugh and arranges their daughter on her hip again. “Flayn is working now, dear. You can play with her later, okay?” Niamh pouts, but acquiesces, turning her sights back on him again and asking to be picked up. He can never deny any of them anything, so he gives Byleth the toy and takes their daughter into his arms.

Flayn waves goodbye as she guides the students away, and Byleth fiddles with the forgotten fish plush as Niamh settles for tugging at his hair instead. “What brings you out here?” He asks as they walk back the way he came, gently catching Niamh’s hand in his own. So small, so fragile.

“Niamh was getting a bit fussy cooped up in the office. I thought a walk outside would calm her down.” Byleth reaches out to pinch their daughter’s cheek lightly. Niamh squeals and hides her face in his neck, peering at her mother from beneath her fringe.

“She gets it from you,” Seteth teases, rubbing a hand on their daughter’s back. “I remember you would get restless after a few hours of work. Before I knew it, you had run off someplace to take a break.” 

Byleth sighs a bit too dramatically. “I never understood how you managed to sit behind a pile of paperwork all day long. I still don’t.” 

The cathedral is empty now that the choir has left. The heels of her shoes click lightly on the floor and echo around them as they walk down the aisle towards the statue of the Progenitor God standing on the dais, framed by grand stained glass windows. It was restored once the war was over, and the sculpture remains in perfect condition years later thanks to the careful work of those hired by the museum. 

Being in the monastery again brings back many memories, but the cathedral and the Goddess Tower bring forth the most special ones, all of which have his wife as the starring role. Regardless of how many times he visits these places, he always finds himself reminiscing the past.

Seteth doesn’t realize he has spaced out in his musings, and therefore hasn’t paid attention to a single word she’s said, until Byleth playfully bumps her hips with his and brings him back to the present. “What’s in your mind?” 

“You,” he replies immediately, turning to look at her, taking in the uniform she wears, the black high waisted pencil skirt and the white button up with embroideries on the shoulders. He lowers his voice to a quiet whisper as he steps closer, taking her hand to kiss her knuckles softly. “Whenever I am here, I remember you standing in this very place, wearing your wedding gown, lilies in your hair and an arrangement of peonies in your hands.” 

A blush rises on her cheeks, and Byleth lowers her head to laugh bashfully, pressing herself to his side. “I remember you standing here as well in white and golden robes. You were so handsome, so beautiful.” She lifts a hand to cup his own pinkened cheeks. “But then again, you always are.” 

“You are one to talk.” Seteth turns his face to kiss her palm, his ears hot and twitching in elation. “You made me so happy when you accepted my proposal, when you said yes. There is not a day when I am not thankful for having you with me.”

“What’s gotten into you today?” She’s clearly embarrassed, now hiding her face in his chest. Seteth chuckles lightly and wraps an arm around her shoulders, holding her close as he buries his nose in her hair. 

Tired of being ignored, Niamh whines and pats her little hands on Byleth’s cheek to get her attention. Seteth watches as his wife smiles beautiful and wide at their daughter and arranges Niamh’s pale hair to cover her pointed ears, gently booping her nose afterwards. Niamh scrunches up her face and reaches for the fish plush, flexing her little fingers, and hugs it to her chest when Byleth gives her the toy.

“We should renew our vows here,” he muses to himself in murmurs, but of course Byleth picks it up. 

“Do I get to wear a new dress?” She asks, her smile as teasing and lovely as her eyes.

“You always do.” Every century that passes, wherever they are, they dress in white to renew their vows with Flayn as their single witness. Some would say it’s sappy, but he likes it this way. And now they have little Niamh to bear witness too. All the more reasons to renew their vows. “I would like to see you in that dress again, however.” 

She rests a hand on the nape of his neck, tugging with intent. “Consider it done.” 

Byleth rises on the tips of her toes to press a kiss to his mouth, sweet and gentle and lingering. He exhales slowly, arm tightening around her, hoping to convey all his love for her in that single, simple touch of their mouths together. Given the way she smiles when they pull apart, he knows he’s succeeded.

**Notes for the Chapter:**

> This is the only prompt out of four that I began writing and actually finished. Are you proud of me yet- 
> 
> When I first began putting together my [setleth playlist](https://open.spotify.com/playlist/1l7UmBixKoGFt7fDwKj32c?si=glXviID6R6KqZjImfPyDnw), I rediscovered the song [Legendary Lovers](https://www.youtube.com/watch?v=2t2WLGW2Kvs) and I just kept imagining this whole fic as I listened to it, mainly how they would meet in the bridge and walk together to the cathedral by the end of the song. 
> 
> As for their child, I was looking up names I thought Niamh was pretty fitting. Mostly because it is said she was the daughter of the God of the Sea, and we all know how the ocean means a lot to Seteth and Flayn. It also means "bright."
> 
> Now for a bit of shameless self promotion, I have [another fic](https://archiveofourown.org/works/23180953) going on that is inspired by Twilight BUT PLEASE...... it's not actually Twilight, I'm just taking some scenes from it that would be funny with setleth in their place so. Please. Give it a chance akshsakjf

**Author's Note:**

> | [tumblr](https://chinarai.tumblr.com/) | [twitter](https://twitter.com/chinaraii) | [carrd](https://chinarai.carrd.com/) |


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